panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 951
Starting stack trace...
panic(ffffffff8336ca8a) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff833ac1a0,ffffffff833b908a,3b7,ffffffff833e2f2c) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80003c475d78,ffffffff83363f07) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952
pppx_if_destroy(205b9a,ffff80003c475d70) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,1,2000,ffff80003c46f228) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80003c43f930) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd807534adc0,1,fffffd80097fb478,ffff80003c46f228) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd805dc99478,ffff80003c46f228) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd805dc99478,ffff80003c46f228) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd805dc99478,ffff80003c46f228) at fdrop+0x121 sys/kern/kern_descrip.c:1267
closef(fffffd805dc99478,ffff80003c46f228) at closef+0x192 sys/kern/kern_descrip.c:1251
fdfree(ffff80003c46f228) at fdfree+0x116 sys/kern/kern_descrip.c:1182
exit1(ffff80003c46f228,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80003c46f228,ffff80003c43fca0,ffff80003c43fbf0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80003c43fca0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c43fca0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x74231ea3e5f0, count: 242
End of stack trace.